How do you simplify #2/3 + 1/5 - 1/2#?

1 Answer
Aug 2, 2016

Answer:

#11/30#

Explanation:

#color(blue)("Considering the common denominator")#

5 will be a factor of any number (apart from 0) that end in 5 or 10
Unfortunately a number ending with 5 can not be divided exactly by 2. So the common denominator has to be a one of the 'tens'

Note that #3xx10 = 30 =># the common factor is 30
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#color(blue)("Method of changing to equivalent fractions")#

Multiply a number by 1 and you do not change its value. You can however change the way it looks.
Example: #3xx1 -= 3xx5/5 -=15/5#

The inherent value is still three but it looks different.
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(blue)("Answering the question")#

Write as: #(2/3xx10/10)+(1/5xx6/6)-(1/2xx15/15)#

#( (2xx10)/(3xx10) )+((1xx6)/(5xx6))-((1xx15)/(2xx15)) #

#20/30+6/30-15/30#

#color(brown)("You can now directly add/subtract the top numbers")#

#(20+6-15)/30 =11/30#